Secant pile walls are crucial in the construction of fossil-fuel power plants for water exclusion purposes. The construction time is the most critical factor that influences the entire construction project. Thus, shortening the time needed for building secant pile walls requires further investigation. Secant pile walls are not required to be constructed in any particular order; typically, site engineers assign construction crews to first build several primary bored piles, and then build secondary bored piles. However, building secant pile walls in this sequence generally requires the primary bored piles to be excessively cured and hardened. The construction of secondary bored piles in this manner thus results in construction difficulties, wasted construction time, and poor construction quality. To address this practical problem, this study adopted a genetic algorithm to investigate the optimal number of primary bored piles, the curing time, and the number of daily working hours for the construction crew. In addition, the relationship between the curing time for the primary bored piles and the construction time for the secondary bored piles was investigated by using a case study, to ensure the overall research results corresponded to practical operation. The findings of this study can facilitate the saving of construction time in the future construction of secant pile.